Two-digit rotary switch



Sept. 16, 1958 K. w. GRAYBILL 2,852,615

TWO-DIGIT ROTARY SWITCH 2 Sheets-Sheet 1 Filed Nov. 3, 1954 INVENTOR.

KENNETH W. GRAYBILL BY 75m sept- 16, 1958 K. w. GRAYBILL 2,852,615

Two-DIGIT ROTARY SWITCH 2 sheets-sheet 2 Filed Nov. 3, 1954 FIG?) INVENTOR.

vKENNETH W. GRAYBILL ATTY.

TWO-DlGlT ROTARY SWITCH Kenneth W. Graybill, Elmhurst, Ill., assigner to General Telephone Laboratories, Incorporated, a corporation of Delaware Application November 3, 19518, Serial No. 466,697

20 Claims. (Cl. TNB-27.51)

This invention relates generally to automatic switchmg apparatus'. More particularly this invention relates to improvements in rotary switches of the two digit type for use in automatic telephony.

Heretofore automatic telephone systems based on the employment of unidirectional rotary switches in the interests of economy and simplicity of operation, have to a large extent had these advantages offset by the necessity of providing an expensive array of relays to perform group selection. No mechanical selection of groups has been possible heretofore where only the rotary switch is used in the system. Accordingly, it is the primary object ofthis invention to provide a simple and inexpensive rotary switch which will complete the group selection previously performed by means of relays, thereby effecting a substantial reduction in equipment costs.

Another object of this invention is to provide such a rotary switch which will perform wiper selection and group selection by a simple mechanical means in response to digital impulses thereby permitting straightforward direct dialing in a rotary switch system.

It is a further object of this invention to provide a rotary switch capable of both wiper and group selection within its contact bank, the mechanism of the switch being operated by a maximum of two operating electromagnets.

Still another object of this invention is to provide a switching means which is operative in response to a lirst digit dialed to both select from a plurality of wiper sets the wiper set to be used and to select a bank group within which further selection is to be made in response to a second digit dialed or by automatic trunk hunting.

An object complementing the immediately preceding object is the provision of a mechanism eilective through a single rotary positioning movement to perform the selection of both the wiper set and the bank group.

A further object of the present invention is the accomplishment of the objects stated above by means of an arrangement at once simple in operation and easily adaptable to existing rotary switches of the type described in the patent to Graybill et al., No. 2,522,715, September 19, 1950.

Briefly, the objects as set forth above are realized in the preferred embodiment of the instant invention by an arrangement including as an integral component thereof a wiper and contact bank assembly of a type well-known in the art and fully described in the patent to Graybill et al. referred to above. Preferably the contact bank is of the 16 level, 25 position type in which the contacts of the rst live bank positions are used only on the 16th level which level serves as a marking or control level. The remainder of the bank positions are separated into two sections, each of which comprises half of this remaining bank arc. On the marking level the contacts of each of the two sections are strapped together for marking purposes. Thus the contact bank so arranged provides for 100 points, that is, the two sections of the bank as they relate to a preferred tive sets of switch 2,852,6l? Patentes sept. 1e, 195s 2 wipers provide l() separate groups of trunks, each group comprising 10 trunks and each trunk having there conductors. Associated with the marking level is an additional control wiper set adapted to control the rotary stepping mechanism of the switch. The wiper sets are co-rotatively stepped past the contacts by thewell-known stepping magnet and pawl and ratchet mechanism shown in said prior patent. Associated with the live switch wiper sets and individually related thereto are five contact spring assemblies. With each of theftwo sections of the contact bank is individually associated a marking spring assembly, a first marking assembly for the second group of the 16th level bank contacts and a second marking spring assembly for the rst group of the 16th level bank contacts. A magnet operated group selecting lever is provided to accomplish the selection of the spring assembly associated with the one of the live sets of switch wiper sets to be used and is adapted to be rotated with the switch wiper sets. Thus as the switch wipers are stepped in response to dial pulses up to and including live in number the switch Wipers will be stepped to some one of the rst vebank positions, only the 16th level of which, it will be recalled, has its contacts used. The lirst of the two marking spring assemblies is disposed so that the group selecting lever is also in a position opposite this assembly each time the lever is in a position opposite any one of the'w-iper spring assemblies for any one of the digits l to 5 dialed. Thus suppose the digit 5 were dialed, in that case the wipers would be stepped to the fifth bank position and the selecting lever to the fifth spring assembly. When an operating magnet is now actuated both the wiper spring assembly and the iirst marking spring assembly will be operated by the group selecting lever. Circuits, not shown, will be closed for the lifth switch wiper set by the operated wiper spring assembly and the fth switch wiper set will thereby be selected as the operative wiper set of the said five sets of switch wipers. Simultaneously a marking circuit, also not shown, will be closed to the second marking group of the 16th level bank contacts thereby applying a potential to the contacts of this group. If the rotary switch is operated as a selector, the selected switch wiper set will now search for an idle trunk over all of the contacts of its associated contact bank levels except those of the group having the corresponding gro-up of contacts on the marking level made busy. Through this section having the busied group, the selected switch wiper set will be uninterruptedly stepped under the control of the control wiper set associated with themarking level. It should be noted at this point that the searching operation of switch in the afore-mentioned bank group is underl the control of a control wiper included in each of the live sets of switch wipers, resulting therefore in a dual control of the rotary stepping mechanism-by the control wiper set and the control wiper of each of the live wiper sets. Similarly, for any of the other digits 1 to 5 any one of live different sets of switch wiper assemblies would be selected and the contacts in the first half of the bank would be searched.

lf a digit from 6 through l0 is dialed, as for example the digit 8, the group selecting lever will continue to step in response to the dial pulses, past the live wiper spring assemblies, until a trailing extension of the group selecting lever is positioned opposite the third wiper spring assembly. At this point, and for any digit dialed from 6 through 10, the group selectingr lever will be opposite the second marking spring assembly. When the operating magnet is now actuated the third wiper spring assembly and the second marking spring assembly will 'be operated and switch wiper set three will be operative. Now, however, the first marking group of contacts will be made busy by the second marking spring .0 assembly and the rotary switch will search for an idle trunk in the second group `of bank contacts.

At the end of a call the usual release control circuit may be employed to cause off-normal springs on the switch to return it to normal and when the normal position is reached, the control magnet may be released thereby allowing the group searching lever to return to normal.

Additional objects and features of the present invention together with its advantages and manner of operation will be better understood with reference to the detailed description which follows taken in connection with the laccompanying drawings in which:

Fig. l is a plan View of the switch in which a portion of the wiper and group selection section has been broken away to show the inter-relationship of the parts and particularly the details of the wiper and group selecting lever and the operating magnet amature. lt should be noted that switch wiper and group selecting contact spring sets are not included in this view, only the spring raisers for these springs being shown.

Fig. 2 is a side elevation of the switch showing the wiper bank, only four levels of which are shown, and the relative positions of the wiper and group selection section and the rotary stepping section. This view includes the wiper and group selection contact spring sets.

Fig. 3 is a perspective representation as viewed from the underside of the switch wiper and group selecting section of the switch.

Referring now particularly to the iigures of the drawings it is seen that the invention for purposes of description may be conveniently divided into a switch wiper and group selection section and a rotary stepping section including the familiar contact bank assembly. Thus in Fig. 2 these sections are designated as sections 1h11 and 2111i, respectively. All of the parts of the latter section 21N) are mounted upon a one-piece frame 110 which is provided with a pair of oppositely disposed flanges 111 and 112, as shown in Fig. 1, to facilitate mounting of the switch. An arcuate shaped contact bank assembly 113 is held rigidly in place with respect to the other elements of this section 21111 by means of a mounting plate 1143s and mounting means 115. ln the preferred embodiment of this invention the contact bank assembly 113 comprises 16 levels, the contacts 119 and terminals 120 of which are shown in Figs. 1 and 2. It should be noted that only four levels are shown in the side elevation of Fig. 2, it being understood that 16 levels are actually used in the preferred embodiment of the invention. Each of the levels of the bank assembly 113 comprises 25 contacts with two additional contacts being provided as the home positions for the switch wipers to be described. An electromagnet 130 affixed to the one-piece frame by means of an upturned heelpiece 132 of the frame 11b"l operates, by means of its armature 131 when energized, a stepping mechanism consisting of the well-known pawl 136 and ratchet wheel 137 together with an operating coil spring 138, detent 139 and holding spring 14.2 shown generally in Fig. 2. A pair of auxiliary springs 13@ mounted on a turned up portion 132:1 of the frame 110 by mounting means 135 is provided to be operated by an armature lever 133 each time the electromagnet 139 is energized. Associated with the ratchet wheel 137 and co-rotatively mounted on a common shaft 141i there-- with are double-ended switch wipers 141. The wipers 141 are so positioned as to successively engage the contacts 119 as they are rotated step-by-step on the shaft 140 by the stepping mechanism as operated by the electromagnet 1311. it should be understood that each of' the bank levels, 16 in number as indicated above, has associated therewith a pair of the double-ended switch wipers 141. A second set of auxiliary contact springs 143 is affixed to the mounting plate 114 by mounting means 144. The spring set 143 is so positioned as to be engageable by either one of a pair of pins 145 eX- tending from a drum 146 which drum is rotatively mount ed on the shaft and co-rotative with the switch wipers. As the drum 146 is rotated the pair of pins 145 alternately operate the auxiliary spring set 143. The pins are preferably positioned with respect to the switch wipers 141 such that one of the pins 145 will operate the auxiliary spring set 143 when the switch wipers 141 are in their home positions, that is, on the bank contact immediately preceding the first and the bank contact immediately following the 25th bank contact of each level.

ln the preferred embodiment of the present invention the iirst ive contacts are used only on the 16th level which level is employed as a marking or control level only. Thus the first 15 levels include as eifective contacts only those from contacts 6 to 25, inclusive, not including the normal or home contacts. The portion of the contact bank 113 including the contacts 6 to 25 is divided into two sections, each section comprising half of these contacts. Thus on each level the contacts 6 through 15 will comprise a first group and the contacts 16 through 25 will comprise a second group. On the 16th level which is the marking or control level -the contacts of the first group, that is, contacts 6 through 15, are strapped together, as are the contacts of the second group, that is, contacts 16 through 25. On the 16th level contacts l through 5 are also strapped together for purposes which will become apparent from the description of the operation of hte invention to follow. The foregoing arrangement of the contact bank makes possible the availability of 10 separate groups of trunks as the two sections of the contact bank are related to iive sets ofswitch wipers. Thus assuming each trunk t-o include three conductors three pairs of the switch wipers 141 will comprise one of each of the live sets of switch wipers, leaving one pair of wipers associated with the 16th, or marking level of the bank to serve as a control wiper set.

Rigidly secured to the drum 146 by mounting means 1417 is a driving arm 1S@ adapted to rotateas the drum 146 is rotated. The arm 1511 is preferablyl composed of a at spring admitting of a slight downwardly deilection for purposes to -be hereinafter made clear. As more clearly shown in Fig. 3 the driving arm 1511 is provided at its extremity with a bifurcation 151 which may be reinforced with turned down lips 152. A guide 153 falling slightly away from the plane of the bifurcation completes the operating end of arm 151i.

Turning now to a consideration of the switch wiper and group selection section 1G11 it is seen from the drawings that the components of this section arc mounted upon or dependent from a mounting plate 10 which in turn is supported by a pair of mounting posts 11 adapted to be secured to the mounting plate 114 of the rotary stepping section 200 and secured thereto by the bolts 12. The mounting plate 11i is positively located with respect to, and forms an additional support for, the shaft litt* of the rotary stepping section Z110 by means oi the threaded bushing 19 which in turn is drilled and adapted to rcceive an extension of the shaft 1411. A jam nut 2.3 secures the ybushing 19 and mounting plate 11) to prevent accidental loosening and at the same time provides a means to adjust the pressure on the shaft 141i. One side of the mounting plate lil is turned up to form a heclpiece 13 for an electromagnet 15 which is secured thereto by any suitable means 14. An armature 16 operatively associated with the electromagnet 15 is pivotally secured to the underside 1of the mounting plate 1i) by means ot pivot pin 17, the mounting plate 1t! being provided with an aperture 20 through which the armature 16 e: ends. The pivot pin 17 may be secured to the underside of the mounting plate 1t) in any convenient manner such as by means of the hinge block 13. Extending at right angles to and integral with the armature 16 and parallelly disposed to the underside of the mounting plate 10 is a fan shaped armature lever 30 having its central portion substantially blanked out as shown in Fig. l. This armaagesageis turev lever 30 is biased downward as--viewed inFig. 2 in a normal positionagainstl a'stop'21 by a flat springv 22, both the stop 21 and the spring 2'2`being aflixed to the underside of' the mounting plate 10 in any convenient manner. The armature lever 3l)J is provided with a circular aperture 24 through Which is freely passed the bushing 19 which extends from the'rnounting plate 10 to the shaft 140 of the rotary stepping section 200. The extremity of the fan shaped armature lever 30 comprises an arcuate portion 30e having the center of its arc on the axis of the bushing 19 and the shaft 140.

A group selecting lever 40 slidably supported on the annature lever 30'is pivoted about the axis of the bushing 19 and the shaft 140 and is rotatably mounted in the circular aperture 24 `of the armature lever 30 by means of a ange which may be formed by a circular upset of the lever 40. A hat-headedV set-screw holds the anged selectedlever in 'slidable contact with the armature lever 30. A lug 41 on the group selecting lever 4th is adapted to be brought against an arm' 30a formed by the blanked out portion of the armature lever 30, A tension spring 42 is extended between a post 43 on the selecting lever 40 and a post 44 on an extension 30h of the armature lever 30, the spring 42' tending to maintain the selecting lever 40 in a normal position with the lug 41 brought against the arm a of the armature lever 30. A clip 40C formed by a turned over extension of the selecting lever 40 maintains the lever 40 in slidable contact with the arcuate portion 30C of the armature lever 30. Returning for a moment to the rotary stepping section 200, the driving arm 150 was described as being provided with a bifurcation 151 reinforced withthe turned down lips 152 at its extremity. As shown in Fig..2 and more clearly in Fig. 3 this bifurcation 152 is adapted to-slidably engage the-lug 41 of the group selecting lever dit. Thus it is evident from Figs. l and 3 that, as the switch wipers and the drum 146 are rotated in a counter-clockwise direction, as viewed inFig. l, by the stepping mechanism as operated by the electromagnet 130, the driving arm 150 rigidly connected to=the drum 146 will also rotate and in turn, by means of the bifurcation Elco-operating with the lug 41, rotate the group selecting lever 40 about the axis of the shaft 146 against ther bias of the tension spring 42.

Arranged 011 the plate 111 is a parallel grouping of ve at springrraisers 50a, b, c, d and e each affixed at one end by any suitable means, such as the mounting screws 52, to the plate 1G and having the other end protruding beyondfthe limits of the plate 10. An additional pair of atspring raisers 51a and b disposed on either side of spring grouping 59A and parallel therewith is also mounted on the plateltl by similar. means 5'2, completes the assembly'of spring raisers utilized to selectively operate the spring sets oil/a, b, c, d and e, and 61a and b associated with the atspring raisers Sila, b, c, d and e, and 51a and .5', respectively, and shown in Fig. 2. As will be explained hereinafter each of the group of spring ,sets 60 is associated respectively with one of the tive sets of switch Wipers 141 and each of the pair of spring sets 61 is associated respectively with one of the two groups of contacts 119 on the 16th level of the contact bank. Each of the groups of flat spring raisers 5t) and 51 is provided on the protruding extremity ywith a downward extending loperating bushing 53 adapted to be engaged by the group selecting lever 40. The operating bushings 53 of the spring raiser group 50 are arranged in an arc having its center on the `axis of the shaft 14) and angularly spaced to correspond to the angular spacing of the bank contacts 119 of the rotary stepping section 230 which are also arranged in arcs having their centers on the axis of the shaft 140. To engage the operating bushings 53 of the spring raisergroup 50, the group selecting lever 40 is provided with two arcuate extensions 40a and 40b at its operating end. The: entireend' of the lever 4i) as a 6 result assumes the form of an arcuate cross-member hav'- ing itscenter on the axis ofthe shaft 140. It is noted from Fig. l that the outer radius of the arcuate crossmember including the extensions 40a and 4Gb is such that as the selecting lever 4th is pivoted about the bushing 19 it will clear the arc of operating bushings of the spring raisers Stia, b, c, d, and e. To engage the group of operating bushings of the spring raiser group Si) a pair of lugs 40a' and 4017' is provided extending outwardly from the extensions 40a and 4Gb and radially from the axis of the shaft 14). The lugs 40a and 4Gb are angularly spaced to correspond to the angular spacing between six rof the bank contacts 119. Thus, as is evident from Fig. 1, as the switch wipers 141 are advanced step-eystep past the rst five bank contacts the group selecting lever d@ will also be rotated by action of the driving arm 159 and the lug 40a will be advanced past the operating bushing 53 of the spring raisers 59a, b, c, d, and e. lf the switch wipers 141 are now advanced past the next bank contacts, the lug 40h will be advanced step-oystep past the operating bushings 53 of the 5 spring i raisers 50a, b, c, d, and e.

Returning now to the pair of spring raisers 51a and 51b, the operating bushings 53 of those springs are also arranged on an arc having its center on the axis of the shaft lift-tlf, the radius of the arc being such that arcuate cross-member including extensions 40a or 4Gb of the group selecting lever 40 will tbe in a position to engage the operating bushing 53 of either of the spring raisers 51a or Sib as the lever 4t) is rotated. The angular separation of the bushings 53 of the spring raisers '51a and 51h is so related to the arc length Yof the cross-member of the group selecting lever 40 that as the lug 40a of the extension dil-tz is advanced 'to a position opposite the' operating bushing 53 of the fh spring raiser 5de the extension ttm will have advanced to a position immediately preceding the bushing 53 of the spring raiser 51h. At this point the lug 40h will be in a position immediately preceding the lirst spring raiser 50a and thetrailing extension 41th will still be engageable with the bushing 53 of the spring raiser 51a. Further, the bushings 53 of the springs 51a and 51h are so separated With respect to the larc length of the said cross-member that if the selecting lever4tl is now advanced one more step thelug 49a will pass from co-operation with the bushing 53 of the spring raiser Site and the extension 46a will now `be positioned opposite the bushing S3 of the spring raiser 51b. At this point also the lug 4Gb will be positioned opposite the bushing 53 of the spring raiser 50a and the trailing extension dit!) will be withdrawn from co-operation with the bushing 53 of the spring raiser 51a. Thus it is evident that one of the pair of spring raisers 51a and 51h will always be selected by the group selecting lever 4t) in connection with the selection of any one of the group of spring raisers Sit. To provide adequate clearance for the bushings S3 of the spring raisers 51a and 51b the mounting plate 10 may be recessed as required as shown in Fig. l.

When the group selecting lever 40 has been advanced to a-predetermined position, that, is with lone of its lugs 40a or 40h' in a position opposite one of the operating bushings 53 of the group of spring raisers 50 and the arcuate cross-member in position opposite the bushing 53 of one of the pair of spring raisers 51a or 51h, the operating magnet 15 is operated to cause the armature 16 and its lever 3() to be pivoted about the pivot pin 17 in a counter-clockwise direction as viewed in Fig. 2 against the bias of the flat spring 22. Operation of the armature lever 30 brings the group selecting lever 4t) towards the mounting plate 10 at the same time bringing the effective lug 40a or 40h into engagement with the bushing 53 of the selected one Iof the group of spring raisers 50 thereby raising the selected spring raiser which in turn operates its associated spring set. As will be hereinafter more particularly explained, operation ofthesaid associated spring set closes an operated circuit (not shown) to the selected one of the switch wiper sets which will then be the effective wiper set in operation. At the same time that one of the group of spring raisers Sti is operated by the group selecting lever 40 and the armature lever 34B one et the pair of spring raisers 51 is also operated thereby operating its associated contact springs to mark one of the two groups of contacts on the 16th level of the contact bank. To prevent engagement of the armature lever Sti with the bushing 53 of the spring raiser 51 not selected by the selecting lever d@ as the armature lever 3d is operated clearance is provided by the recesses lilla in the armature lever 30.

To insure the positive positioning of the group selecting lever d@ with respect to any one of the group ot spritz raisers Si? and to lock the lever d@ in position the lever 4 0 is provided with locating means such as a stop pin 55 adapted to engage any one of an arcuate series of locating stops which may conveniently consist of the arcuate series of drilled holes 56. The lug 41 of the selecting lever il and the bifurcated end 151 of the driving arm 15@ cooperate in a manner such that as the operation of the armature lever 3@ by the magnet 13G moves the stop pin 55 into engagement with any one of the drilled holes 56 the lug il will be raised out of engagement with the bifurcation 151 of the driving arm 159. The driving arm 150 will now be free to continue rotation with the switch wipers 141 as they advance over the remainder of the contacts 119 of the contact bank without further advancing the group selecting lever dit.

Having thus described the components and structural details of the invention the manner of operation will now be considered. Operating as a l() point selector with lt) groups of trunks, each trunk having three conductors as described hereinbefore, a 16 level 25 point rotary switch would be used with the wipers normally resting in the 26th position which is an unused bank space directly in front of the rst bank Contact position. It will be the function of the switch according to the present invention to select one of tive sets of wipers and one or the other of the two sections of the bank arc which are fully equipped with contacts. In response to a iirst digit dialed, say the digit 1, the wipers 141 will advance by operation of the rotary magnet 130 in accordance with the number of impulses received, in this case, one. It should be recalled that the wiper sets l to 5 will not, during the rst 5 steps, engage any connected bank contacts since these contacts are effective only on the 16th or marking level. Because of the operation of the driving arm 151i in co-operation with the lug 41, the group selecting lever 40 also advances one step and its lug 40a' positions itself under the bushing 53 of the spring raiser 50a and its associated contact springs controlling the circuit (not shown) of the first switch wiper set. The arcuate crossmember extension 4th: of the selecting lever 40 has been and is, at this point, still in alignment with the bushing 53 of the spring raiser 51a and its associated contact spring set. After the rst digit, here digit 1, has been dialed, control circuits not shown, of a type well-known in the art will energize the operating magnet which, when operated, will select the switch wiper set #l by operating the armature lever 30 and selecting lever 4t? which in turn operates the spring assembly associated with the spring raiser 50a. At the same time that the spring raiser Stia is operated by the armature lever 4l) the spring raiser 51a is also operated by the selecting lever 4t) there*- by operating its associated spring assembly. Operation of the spring raiser 51a and its contact spring assembly will place ground on the second group of strapped contacts on the 16th level thereby busying that section. As the selecting lever is operated, the lug 41 is withdrawn from cooperation with the driving arm 150 and the driving arm 150 and the switch wipers 141 are now free to rotate without further advancing the group selecting lever 40 which is held in position by the stop pin 55.

Since, as was seen hereinbefore, the iirst 5 contacts on the 16th level are also strapped together and are now connected to ground by a circuit not shown, the switch wipers 141 will be advanced to position 6 or the rst bank contact 119 in the rst group of trunks. The switch can now search for an idle trunk in the neXt l0 succeeding contacts and, finding one, the switch will have performed its function. Should all the trunks in the first group of l0 contacts be busy, the switch wipers 141 will be automatically driven over the second group of 10 contacts due to the ground placed on these contacts 119 by the operation of the spring raiser 51a and its associated contact spring assembly and the wipers 141 will continue rotation until they reach the normal or home position. ln a similar manner any one of the live different sets ot` wipers 141 can be selected and the contacts 119 in the tirst section of the bank would be searched for an idle trunk.

If a digit from 6 to 10 is dialed, say the digit 8, the selecting lever 40 will be advanced eight steps as hereinbefore described in response to the dialed pulses. The lug 40a of the lever 40 will now have passed beyond the 5th spring raiser Stle but the lug 40h will be positioned in alignment with the 3rd spring raiser 50c. The trailing extension 40h of the lever 40 will also have passed from alignment with the spring raiser 51a. However, the extension 40a will now be in alignment with the spring raiser 511;. Thus for any digit dialed from 6 to 10 one of the spring raisers 50 and the spring raiser 51h will be operated when the magnet 15 and armature lever 30 are operated. When the digit 8 is dialed, therefore, the third switch wiper set will be selected but the spring assembly associated with the spring raiser 51b will, when the operating magnet 15 is operated, place ground on iirst group of strapped contacts on the 16th level thereby preparing the switch for searching in the second section of the bank. It will be noted that for the operation of the switch in response to a digit dialed from 6 to l0 the switch wipers 141 will be stepped in response. to the dial pulses past the iirst ve bank positions into the rst section of the bank. Thus in response to the dialed digit 8 the switch wipers 141 will be stepped to the third contact in the irst section of the bank. When the magnet 15 then operates the armature lever 30 the driving arm 150 will be disengaged from the group selecting lever 40 which has been locked from further rotation by the stop pin 55 which has engaged its locating means 56. Because of the ground potential placed on the strapped contacts of the rst section of the 16th level the switch Wipers 141 will be stepped, under the control of the control wiper set, through the remaining portion of this section to the first contact of the second section of the bank. If no idle trunk is encountered in this section the switch wipers will be driven one more step to their home position.

When the switch wipers 141 have been restored to their normal position the operating magnet 15 will be deenergized thereby restoring the armature lever 30. As the stop pin 55 is disengaged from the locating means 56 the group selecting lever 40 will be restored to its normal position by action of the tension spring 42. The lug 41 will engage the guide 153 of the driving arm 150 as the selecting lever 40 is restored thereby slightly deiiecting the driving arm until the bifurcation 151 again fully engages the lug 41. The switch is now fully restored to normal and is now in condition to be re-operated.

The operation of the switch has been described in the foregoing with respect to its employment as a selector switch in automatic telephone applications. That is, the switch in its rst stage of operation selected in response to dial pulses, a switch wiper set and the group of bank y contacts in which the wipers were to be operated. In its second stage of operation the switch operated automatically to Search for an idle trunk in the group selected. The switch as embodying the present invention may also be operated as a connector in which the second stage of its operation, the selection of a particular trunk within the aendern selected group, is also `accomplished in response to dial pulses. In this application it is necessary that the switch Wipers stop after the first digit has been dialed on either contact of the first five. contacts or contact l0 offirst group of bank contacts. This is necessary in order that the stepping in response to the second digit dialed may begin on the first contact of each bank group. This may be accomplished by strapping only the first 4 of the first five contacts and only the rst 9 of the contacts of the first group of contacts on the 16th level. Thus contacts 5 and l5 of the. 16th level will not be strapped and will receive their ground potential, through external circuit means when the wipers are to be automatically driven past these positions.

While what has been describedis considered to be the` preferred embodiment of this invention it is understood that. various modicationsmay be made in the structure and arrangement of the partswithout departing from the true spirit and scope of the invention as defined in the appended claims.

What is claimed is:

l. A rotary selecting. switch comprising a plurality of co-rotatable switch wipers, a. contact bank comprising a plurality of bank levels associated respectively with each of saidplurality of switch wipers, a plurality of contact springs, each electrically associated with only one of said plurality of switch wipers, a spring operating lever, means for positioning said spring operating lever into co-operation with a predetermined oneof said plurality of-contact springs, and magnet means `for actuating said spring operating lever, said magnet means energized to actuate said spring operating lever to thereby select the associated one of said pluralityof switch kwipers as the eiective wiper when the associated predetermined contactspring of the said one switch wiper is `operated by. said actuated spring operating lever.

2. In combination in a rotary selecting switch, a plurality of co-rotatable switch wiper sets, a contact bank comprising a plurality'of bankn levelsassociated respectively with each of said plurality of switch wipers, a plurality of sets of contact springs, each set of springs connected respectively to only one of said plurality of switch wiper sets, means for rotating said plurality of switch Wiper sets, said rotating means rotating saidl switch wiper sets a first predetermned amount, arotatable spring operating lever, a driving arm co-rotatablewith said plurality of switch wiper sets, said drivingiarm engaging said spring operating lever to rotate said lever into co-operation with a predetermined one of said plurality of contact spring sets as saidplurality of switch Wiper sets is rotated said first predetermined amount, andfmagnettmeans energized at the completion of said rotation of said switch wiper sets said first predetermined amount.. to operate said spring operating lever, operation of saidlever in turn operating the said predetermined one of said. plurality of Contact spring sets to thereby render operative the switch wiper set or" said plurality of switch wiper sets associated with the said operated contact spring-set,'operation of said spring operating lever also withdrawing -said lever from engagement with said driving arm y'to permit afurtherrotation of said plurality of switch wiper sets without further rotating said spring operating lever.V

3. ln combination in a rotary selecting switch, a plurality of switch Wiper sets, a contact bank for said switch wiper sets vcomprising a` plurality of bank contact levels, all ofthe said levels respectively associated with the said plurality of switch Wiper sets, aplurality of contact spring sets electrically connected respectively to said plurality of switch wiper sets, a first'mag-net means for rotating said plurality of switch wiper sets from anormal position a predetermined first amount and. a second amount, rotatable spring operating. means, means for rotating said spring operatingl means from anormal position responsive to the-rotationtof said plurality of switch wiper sets from a normal position, said rotation of said rotating means. said predetermined rst amount positioning said spring operating means into co-operative relation with a selected one of said contact spring sets, a second magnet means operated at the completion of said rotation of said switch wiper sets said first amount to operate said spring operating means, operation of said spring operating means operating said selected one of said contact spring sets to thereby render operative said switch operating means to said normal position upon the restoration of said switch wiper sets to said normal position.

5. In combination in a rotary switch, a plurality of co-rotatable switch wiper sets, a contact bank comprising a plurality of contact levels associated respectively with said plurality of switch wiper sets, each of said levels comprising a first and a second group of bank contacts, a plurality of contact spring sets associated respectively with said plurality of switch wiper sets, operation of any one of said contact spring sets rendering operative the switch wiper set respectively associated with said operated spring set, an additional pair of contact spring sets associated with said tirst and said second groups of bank contacts on one of said bank levels, operation of one of said pair of contact spring sets marking its associated group of bank contacts, a first magnet means for rotating said switch wiper sets a predetermined rst amount and `a second amount, a spring set operating lever rotatable from anormal positiornsaid lever operative to operate one of said plurality of contact spring sets and one of said pair of Contact spring sets, rotating means responsive to said rotation of said switch wiper sets said predetermined rst amount for rotating said spring set operating lever into cooperative relation with a selected one of said plurality of contact spring sets and a selected one of said pair of contactspring sets, a second magnet means, said second magnet means energized at the completion of said rotation of said switch wiper sets said predetermined first amount to operate said spring set operating lever, said spring set operating lever inturn operating said selected one of said plurality of contact springs and said selected one of said pairV of contact springs.

6. In a rotary switch, the combinationV as claimed in claim 5, said first magnet means operated to rotate said operative switch wiper set said second amount in a selected one ofsaid bank contacts groups as determined by said marking of one of said bank contact groups on the said one of said bank levels.

'7. A rotary selecting switch comprising a plurality of co-rotatable switch wiper sets including a control wiper set, a contact bank comprising a plurality of bank levels associated respectively with said plurality of switch wiper sets including a marking level associated with said control wiper set, each of said bank levels comprising a first and a second contact group, a group of contact spring sets associated respectively with said plurality of switch wiper sets, operation of. said contact spring sets rendering operlative said associated switch wiper sets, an. additional pair of contact spring sets associated respectively with said first and said second group of contacts on said marking level, operation of said pair of contact springs marking `said associated bank group on said marking level, a first magnet means energized to rotate said plurality of switch wipers a predetermined first amount and a second amount, a spring set operating lever rotatable from a normal position, operation of said lever operating one of said group of contact spring sets and one of said pair of contact spring sets, a driving arm co-rotatable with said plurality of vswitch wiper. sets, saidY driving arm engageable with said spring set operating lever to rotate said lever from a normal position into cooperation with a selected one of said group of contact spring sets and into co-operation with a selected one of said pair of contact spring sets, a second magnet means energized to operate said spring set operating lever at the completion of said rotation of said switch wipers said predetermined first amount, said operation of said lever also withdrawing said lever from engagement with said driving arm, said tirst magnet means rotating said operative switch wiper set said second amount in said associated bank level and in the one of said bank contact groups as determined by the said marked contact group of the said marking level,

8. In a rotary selecting switch as claimed in claim 7, locking means associated with said spring set operating lever for locking said lever from further rotation, 'said locking means operative to lock said lever when said sec ond magnet means is energized, said second magnet means de-energized to free said lever.

9. ln a rotary switch as claimed in claim 8, restoration means for restoring said spring set operating lever to said normal position, said restoration means operated at said dre-energization of said second magnet means.

l0. A rotary selecting switch comprising a plurality of co-rotatable switch wiper sets, Said plurality of wiper sets including a control wiper set, a contact bank comprising a plurality of bank levels associated respectively with said plurality of switch Wiper sets, said plurality of bank levels including a marking level associated with said control wiper set, each of said bank levels comprising `a tirst and a second contact group, Aa group of contact spring sets associated respectively with said plurality of switch wiper sets other than said .control wiper set, operation of one of said spring sets of said group of contact spring sets rendering operative said associated switch wiper set of said plurality of switch wiper sets, an additional'pair of contact spring sets associated respectively with said rst and said second `contact group on said marking level, operation of said additional contact spring sets marking said contact groups on said marking level, a rst magnet means for rotating said plurality of switch wiper sets, said rst magnet means energized responsive to a single series of digital impulses to rotate said plurality of switch wipers a predetermined tirst amount, a rotatable spring set operating lever for operating said contact spring sets, operation of said lever simultaneously operating one of said additional pair of contact spring sets, a driving element corotatable with said plurality of switch wiper sets, said driving arm engaging said spring set operating lever to rotate said lever into co-operative relation with a selected one of said group of Contact spring sets and a selected one of said pair of contact spring sets as said switch wipers are rotated said predetermined iirst amount responsive to said single series of digital impulses, a second magnet means energized at the completion of said rotation of said switch wipers said lirst amount to operate said spring set operating lever to thereby operate the said selected one of said group of contact spring Sets and said selected one of said additional pair of contact spring sets whereby respectively said associated switch wiper set is rendered operative and said associated contact group is marked on said marking level.

ll. In a rotary selecting switch as claimed in claim l0, means for locking said spring set operating lever, said operation of said lever withdrawing said lever 'from engagement with said driving element and `actuating said locking means to thereby lock said lever from further rotation, said rst magnet means energized to rotate said operative switch wiper set a second amount through one of said contact groups, the rotation of said control wiper set through said marked contact group on said marking level controlling the said energization of said first magnet means for said rotation said second amount.

12. In a rotary selecting switch as claimed in claim ll, said first magnet means energized to rotate said operative switch wiper set a predetermined third amount through vthe contact group on said associated bank level other than the contact group having its corresponding contact group marked on said marking level.

13. A rotary selecting switch comprising a plurality of ctx-rotatable line wiper sets and a control wiper set, a contact bank for said wiper sets, said contact bank comprising a plurality of bank levels associated respectively with said plurality of line wiper sets and a marking level associated with said control wiper set, said contact bank divided into a iirst, a second and a third group of bank levels, said rst group of bank levels having contacts only on said marking level, a plurality of Contact spring sets associated respectively with said plurality of line wiper sets, an additional pair of contact spring sets associated respectively with said second and said third contact group on said marking level, operation of one of said plurality of contact spring sets rendering operative its associated line wiper set and operation of one of said additional pair of contact spring sets causing a marking potential to be applied to the contacts of its associated contact group on said marking level, a irst magnet means including an energizing circuit for rotating said wiper sets from a normal position, said energizing circuit responsve to a first single series of digital impulses transmitted thereto to position said control wiper set on a selected one of said contacts of said first or second group of contacts on said marking level, a spring set operating lever, saidlever co-rotatable with said wiper sets from a normal position and adapted to simultaneously operate any one of said plurality of contact springs Iand either one of said additional pair of contact springs, a driving element corotatable with said wiper sets and adapted to engage said spring set operating lever, said driving element positioning said lever into co-operation with a selected one of said plurality of contact spring sets and a selected one of said additional pair of contact spring sets as said control wiper set is positioned on a selected one of said contacts of said first or second group of Contacts on said marking level, a second magnet means energized at the completion of said positioning `of said control wiper on said contact of said rst or second group of contacts on said marking level to operate said spring set operating lever to thereby render operative a selected one of saidV line wiper sets and to cause a marking potential to beY applied to the contacts of the said second or said third group of contacts on said marking level, and locking means for locking said spring set -operating lever from further rotation, said operation of said lever withdrawing said lever from engagement with said driving element and operating said locking means, said energizing circuit of said first magnet operated responsive to said marking potential on said contacts of said second or said third group of contacts on said marking level as encountered by said control wiper set to cause said first magnet means to successively position said selected line wiper set on said contacts of said contact group having its corresponding` contact group marked on said marking level.

14. In a rotary selecting switch as claimed in claim 13, said energizing circuit of said first magnet means operated to cause said first magnet means to position said selected line wiper set on a predetermined one of said associated contacts lof said contact group other than the contact group having its corresponding contact group marked on said marking level, means for restoring said spring set operating lever to said normal position, said second magnet means energized at the restoration to said normal position of said wiper sets to free said locking means to thereby free said spring set operating lever, said restoring means thereupon restoring said Alever to said normal position.

l5. In a rotary selecting switch as claimedi n claim 14, said energizing circuit of said lirst magnet means operated responsive to a second series of digital impulses transmitted thereto to cause said iirst magnet means to position said selected line wiper set on a selected one of said associated contacts of said contact group other than the contact group having its corresponding contact group marked on said marking level.

16. A rotary switch comprising a co-rotatable line wiper and a control wiper, a contact bank comprising contact levels associated respectively with each of said wipers, each of said levels divided into a -iirst and a second contact group, a first and a second contact spring set associated respectively with said iirst and said second contact group on said levels associated with said control wiper, operation of said first or said second contact spring sets causing Ea marking potential to be applied to said respective associated iirst or said second contact group, a tirst magnet means for rotating said Wipers, said magnet means energized to rotate said wipers a first predetermined amount, a spring set operating lever, said lever adapted to operate either one of said iirst or said second contact spring sets, a driving member co-rotatable with said wipers, said member adapted to engage said spring set operating lever and rotate said lever into co-operative relation with a selected one of said contact spring sets as said wipers are rotated said first predetermined amount, and a second magnet means energized at the completion of said rotation of said wipers said first amount to operate said spring set operating lever, said lever thereby operating said selected one of said first or said second contact spring set, operation of said selected contact spring set causing said marking potential to be applied to said associated contact group on said level associated with said control wiper, said irst magnet means energized to rotate said line wiper in said contact group having the corresponding contact group on said level associated with said control group marked by said marking potential.

17. In a rotary switch as claimed in claim 16, said iirst magnet means operated to rotate said line wiper on a predetermined contact of the said contact group other than the contact group having the corresponding contact group on said level associated with said control group marked by said marking potential.

18. A rotary selecting switch comprising a plurality of co-rotatable switch wiper sets having a plurality of groups or contacts accessible to each set, a selecting wiper rotatable with said wiper set also having a plurality of groups of contacts accessible thereto, means for rotating all of said wiper sets a predetermined amount, means for selecting a particular one of said plurality of wiper sets 14 and for rendering said selected wiper set effective responsive to said rotation of said wiper sets said predetermined amount, and means for selecting a particular one of said groups of contacts accessible to said selected wiper set also responsive to said rotation of said wiper sets said predetermined amount, said rotating means rotating all of said switch wipers a further amount, movement of said selecting wiper over one of said groups of contacts accessible thereto controlling said rotating means to thereby further cause said selected wiper set to select a particular set of contacts only in said selected group of contacts.

19. In a rotary switch, a plurality of sets of wipers, a bank of contacts accessible to each set of wipers, each of said banks divided into more than one group, means for operating the switch in response to a received series of impulses to move the wipers in a rst rotary movement, means operative in a manner dependent'upon the extent of movement of the wipers in said first movement for selecting a particular set of wipers and for determining that only a particular one of the said groups of contacts accessible thereto may be selected, said switch thereafter operated to move the wipers to cause the selected set of wipers to select a set of contacts only in the selected group of contacts.

20. In a rotary switch, a plurality of sets of wipers, a bank of contacts accessible to each set of wipers, each of said banks divided into more than one group, means for operating the switch in response to a received series of impulses to move the wipers in a rst rotary movement, means operative in a manner dependent upon the extent of movement of the wipers in said rst movement for selecting a particular set of wipers and for determining that only a particular one of the said groups of contactsA accessible thereto may be selected, said switch thereafter operated in response to subsequently received impulses to move the wipers to cause the selected set of wipers to select a set of contacts only in the selected group of contacts.

References Cited in the file of this patent UNITED STATES PATENTS 1,767,862 Stehlik June 24, 1930 1,900,917 Deakin et al Mar. 14, 1933 2,320,254 Atkins May 25, 1943 2,701,283 Droel Feb. 1, 1955 2,714,631 Unk et al Aug. 2, 1955 

